It has been known that plates can be coupled to shafts utilizing a single notch cut into the bolt surface. Traditionally, the plate has a D-shaped hole with a cross-section which corresponds to the cross-section of the notch disposed in the bolt is placed over the bolt and held using a threaded fastener.
Often, the plates are subject to torsional loading, which imparts torsional loading to the bolt. Often, designs require that these bolts have a particular torsional strength to ensure that the flange does not become dislodged from the bolt when loaded. In order to maintain the relative position of the plate with respect to the bolt during the torsional loading, the interaction of the plate with the bolt must be such that plastic deformation of the interface does not occur. For this condition to occur, large portions of the bolt surface have been removed to allow for proper interlocking of the members.
The notched bolt, because of its reduced cross-sectional area, has significantly reduced strength. As such, to maintain load requirements, the diameter of the bolt is typically significantly increased to compensate for the weakness in the threaded portion of the fastener. This increases cost and weight of the assembly.